Datasheet

 2012 Microchip Technology Inc. Preliminary DS41639A-page 309
PIC16(L)F1454/5/9
26.0 UNIVERSAL SERIAL BUS
(USB)
This section describes the details of the USB
peripheral. Because of the very specific nature of the
module, knowledge of USB is expected. Some high-
level USB information is provided in
Section 26.1
“Overview”
only for application design reference.
Designers are encouraged to refer to the official
specification published by the USB Implementers
Forum (USB-IF) for the latest information. USB
Specification Revision 2.0 is the most current
specification at the time of publication of this document.
26.1 Overview
This device contains a full-speed and low-speed
compatible USB Serial Interface Engine (SIE) that
allows fast communication between any USB host and
the microcontroller. The SIE can be interfaced directly
to the USB by utilizing the internal transceiver. Some
special hardware features have been included to
improve performance. Dual access port memory in the
device's data memory space (USB RAM) has been
supplied to share direct memory access between the
microcontroller core and the SIE. Buffer descriptors are
also provided, allowing users to freely program
endpoint memory usage within the USB RAM space.
Figure 26-1 presents a general overview of the USB
peripheral and its features.
FIGURE 26-1: USB PERIPHERAL AND OPTIONS
3.3V LDO Regulator
P
P
FS
EN
D+
D-
USB
SIE
USB Clock from the
Oscillator Module
USB Control and
Configuration
512 byte
USB RAM
USB
FSEN
UPUEN
USB PIC
®
Microcontroller
Note
1: Possible optional setup for LF parts only. F parts should use internal LDO to power V
USB3V3.
2: On F devices the regulator is powered by Vdd. On LF devices the regulator is internally bypassed to Vdd.
Vcap
V
USB3V3
(2)
Transceiver
Internal Pull-ups
VDD
(1)
External 3.3V
Supply
3: 496 bytes accessible in both linear and banked data space. 16 bytes accessible in access data space only.
(3)